This is ideal for the process, but any 2 containers will work as long as once fits snug atop the other and can be sealed with a lid. In this lid you will punch a small hole as you would a char tin, except this container will be upside down and the hole will allow oil to drain into the 2nd container as a catchment..
For Ax handles and leather use warm and dip a rag as you would any other oil and spread thin rubbing into the wood or leather, the oil also makes an excellent water proof lure for Beaver.. As the solution cools it will get tacky, if you need to store it can be stored like this by placing a lid on the container, to use again just warm it up on coals. If you desire to make Birch Tar, a great natural adhesive, you will need to further render the oil buy low heat and stirring to release the flammable chemicals by evaporation. It will begin to thicken as it is heated and become pasty, it can then be formed on a stick or in cubes as tar. In the state of oil it is flammable and can be used also as a fuel, but you don't want it to catch fire if you are using it for tar as this will make it brittle.